1. Field of Disclosure
The present disclosure relates to new and improved methods of and systems for reading bar code symbols using visible and invisible sources of illumination during data capture and processing operations.
2. Brief Description of the State of the Art
Today, bar code symbols and labels are used in diverse applications. Typically, a bar code label is printed on a light reflective substrate (e.g. paper) with an ink that is absorptive in the visible-band portion of the electromagnetic spectrum. In such applications, the bar code symbol reader must have a visible source of light (e.g. VLD or visible LED) for reading the visible bar code symbols.
However, in many security-type applications, where access and admission cards and tickets are given out, the security cards bear bar code symbols that are printed with infra-red inks, i.e. inks that reflect only light in the infra-red band portion of the electromagnetic spectrum. In such specialized applications, the bar code symbol reader must have an infrared (IR) source of light (e.g. IR-LD or IR-LED) for reading such IR-based bar code symbols.
A variety of methods have been developed and disclosed in the following patents and patent application Publications to read bar code symbols using visible and/or visible radiation for object illumination purposes, in particular: U.S. Pat. No. 7,036,735 to Hepworth et al, and US Publication Nos. 2006/0113386, 20080283611A1 and 20090065584A1.
While the digital imaging-based and laser-based systems disclosed in these prior art patents possess the capacity to read visible and invisible bar code symbols, in diverse environments, such system are more complex and costly to manufacture than desired in most applications where there is a practical need to read both visible and invisible bar code symbols, but with a greater sense of economy.
In short, there is great need in the art for new and improved ways of simply and reliably reading bar code symbols using either visible or invisible illumination, in the same application environment, avoiding the shortcomings and drawbacks of the prior art apparatus and methodologies.